function sayHello(name: string, age = 20, sex = false) {
    return `Hello from ${name} ${age} ${sex ? 'boy' : 'girl'}`;
}

// let sayHello = (name: string): string|null => {
//     return `Hello2 from ${name}`;
// }

// interface Type {
//     f1: (name: string) => string
// }
// let e = 
export = {
    f1: sayHello
}